Measuring apparatus and method

ABSTRACT

According to one embodiment, a measuring apparatus includes an ultrasonic transmitter, an ultrasonic receiver and an estimator. An ultrasonic transmitter transmits, as a transmission signal, an ultrasonic beam in a plurality of directions. An ultrasonic receiver receives, as received signals, reflected waves of the transmission signal from the plurality of directions, one received signal including a plurality of reflected waves when the transmission signal is transmitted to one direction of the plurality of directions. An estimator that estimates range information from the received signals, based on preliminarily obtained received signals and a preliminarily obtained distance to

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromJapanese Patent Application No. 2017-132917, filed Jul. 6, 2017, theentire contents of which are incorporated herein by reference.

FIELD

Embodiments described herein relate generally to a measuring apparatusand method.

BACKGROUND

In recent years, demands for 2-dimensional range sensors or3-dimensional range sensors for use in automatic driving, or detectionof an obstacle, or mapping, to be mounted on a mobile robot have beenincreasing.

Generally, a millimeter-wave radar or camera, etc. is mounted on avehicle in which an automatic driving function is mounted. As a rangesensor for use in a mobile robot, an ultrasonic sensor that detects adistance to the nearest object, a 2-dimensional range sensor such as alaser range finder (LRF), and a 3-dimensional range sensor such as aLiDAR are used, and furthermore, three-dimensional measurements, etc.using a camera have been performed.

However, a sensor using a laser is high in cost. A sensor using an imagehas a disadvantage of being susceptible to illumination. These2-dimensional and 3-dimensional range sensors are high in cost as awhole.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing a measuring apparatus according to afirst embodiment during machine learning.

FIG. 2 is a diagram showing an arrangement example of an ultrasonictransmitter and an ultrasonic receiver according to the firstembodiment.

FIG. 3 is a diagram showing a scanning example of a transmission signalin the ultrasonic transmitter according to the first embodiment.

FIG. 4 is a flowchart showing an operation when the measuring apparatusaccording to the first embodiment is machine learning.

FIG. 5 is a diagram showing one example of signal waveforms of receivedsignals.

FIG. 6 is a conceptual diagram of learning data according to the presentembodiments.

FIG. 7 is a schematic diagram of deep learning for use in machinelearning.

FIG. 8 is a block diagram showing a measuring apparatus 1 according tothe first embodiment during measuring.

FIG. 9 is a flowchart showing a measuring operation of the measuringapparatus according to the first embodiment.

FIG. 10 is a block diagram showing a measuring apparatus according to asecond embodiment during machine learning.

FIG. 11 is a block diagram showing the measuring apparatus according tothe second embodiment during measuring.

FIG. 12 is a flowchart showing a learning operation of the measuringapparatus according to the second embodiment.

FIG. 13 is a flowchart showing a measuring operation of the measuringapparatus according to the second embodiment.

FIG. 14 is a block diagram showing a measuring apparatus according to athird embodiment during machine learning.

FIG. 15 is a block diagram showing a measuring apparatus according tothe third embodiment during measuring.

FIG. 16 is a diagram showing an arrangement example of a 1-dimensionalrange sensor according to the third embodiment.

FIG. 17 is a diagram showing a scanning example in an ultrasonictransmitter according to the third embodiment.

DETAILED DESCRIPTION

In general, according to one embodiment, a measuring apparatus includesan ultrasonic transmitter, an ultrasonic receiver and an estimator. Anultrasonic transmitter transmits, as a transmission signal, anultrasonic beam in a plurality of directions. An ultrasonic receiverreceives, as received signals, reflected waves of the transmissionsignal from the plurality of directions, one received signal includes aplurality of reflected waves when the transmission signal is transmittedto one direction of the plurality of directions. An estimator thatestimates range information from the received signals, based onpreliminarily obtained received signals and a preliminarily obtaineddistance to an object.

Hereinafter, the measuring apparatus and method according to the presentembodiment will be described in detail, referring to drawings. Note thatin the following embodiments, portions provided with the same referencesigns are each regarded as performing almost the same operation, andoverlapping explanations thereof are skipped as necessary.

First Embodiment

A measuring apparatus according to a first embodiment will be explainedin reference to FIG. 1.

In the present embodiment, the measuring apparatus measures a distancefrom the measuring apparatus to an object existing around the measuringapparatus in an environment to be measured by the measuring apparatus,for example, before shipment from a factory or in initial measurement.Information on the measured distance is acquired as a learning result.In the subsequent measurements, a case is assumed where the measuringapparatus estimates a distance to an object around the measuringapparatus in the same environment, based on the acquired learningresult.

The measuring apparatus according to the first embodiment duringlearning will be explained in reference to the block diagram shown inFIG. 1.

The measuring apparatus 1 according to the first embodiment includes anultrasonic transmitter 11, a transmitting controller 12, an ultrasonicreceiver 13, a multi-dimensional range sensor 21, an answer data storage22, a received data storage 23, and an analyzer 24. Themulti-dimensional range sensor 21, answer data storage 22, received datastorage 23, and analyzer 24 are collectively called a learning module20.

The multi-dimensional range sensor 21 receives multi-dimensional rangeinformation. The multi-dimensional range sensor 21 is a 2-dimensionalrange sensor, such as a laser range finder (LRF), a 3-dimensional rangesensor called a LiDAR (Light Detection and Ranging or Light imagingDetection and Ranging), or a sensor that measures a distance using animage. The multi-dimensional range information is, for example,information in which an angle (or a direction) based on a certainposition is correlated with a distance. In the following, an examplewill be explained where 2-dimensional range information is acquired asmulti-dimensional range information using a 2-dimensional range sensoras a multidimensional range sensor 21.

The answer data storage 22 receives 2-dimensional range information asanswer data from the multi-dimensional range sensor 21 and stores theanswer data.

The ultrasonic transmitter 11 includes a plurality of ultrasonictransmitting devices 111. The ultrasonic transmitter 11 transmits, as atransmission signal, an ultrasonic beam in which an ultrasonic waveprovided with directivity in an azimuth direction, toward surroundingsof the measuring apparatus 1, based on control information from thelater-mentioned transmitting controller 12.

The transmitting controller 12 generates control information forcontrolling the transmission signal transmitted from the ultrasonictransmitter 11. The control information is information related to thedirectivity of an ultrasonic beam, a signal strength, a transmittingdirection (transmitting angle) of a transmission signal, transmissiontiming, etc. The transmitting controller 12 transmits the controlinformation to the ultrasonic transmitter 11 and an estimator 14.

The ultrasonic receiver 13 includes at least one ultrasonic receivingdevice 131. The ultrasonic receiver 13 receives a reflected wave of atransmission signal reflected by an object existing in the surroundingenvironment, and obtains a received signal.

The received data storage 23 receives the control information from thetransmitting controller 12, and receives the received signal from theultrasonic receiver 13. The received data storage 23 correlates controlinformation (e.g., transmitting direction) with a received signal andstores the information as received data.

The analyzer 24 receives 2-dimensional range information from the answerdata storage 22 and receives received data from the received datastorage 23. The analyzer 24 performs machine learning the received dataas an input and the 2-dimensional range information as an output, andgenerates a learning result including an estimation formula. Theestimation formula is a function for estimating 2-dimensional rangeinformation from received data. The machine learning may be performedusing a general technique, for example, a case of an analysis andlearning using deep learning or another neural network is assumed;however, other machine learning techniques may be used.

The learning module 20 may be mounted on the measuring apparatus 1, ormay be arranged separately from the measuring apparatus 1. Aftercompletion of machine learning, the learning module 20 may be configuredto be detachable from the measuring apparatus 1 after a learning resultis generated.

Next, an arrangement example of the ultrasonic transmitter 11 and theultrasonic receiver 13 according to the first embodiment will beexplained in reference to FIG. 2.

The ultrasonic transmitter 11 is arranged in a portion of the measuringapparatus 1. In the example shown in FIG. 2, nine ultrasonictransmitting devices 111 are arranged near a center portion of a sidesurface of the measuring apparatus 1. The ultrasonic transmittingdevices 111 are each, for example, an ultrasonic sensor including anelement generating an ultrasonic wave.

A transmission-phased array is composed of the nine ultrasonictransmitting devices 111. By outputting an ultrasonic wave at the sametime with the three ultrasonic transmitting devices 111 in the verticaldirection being set as one ultrasonic transmitting device array 112 set,a plane wave ultrasonic beam in a vertical direction is formed, and theultrasonic beam becomes a transmission signal.

The ultrasonic beam is caused to scan in an azimuth direction byshifting a transmission timing of transmission signals from three setsof ultrasonic transmitting device arrays 112 (creating a transmissiondelay). An example of using three ultrasonic transmitting devices 111 asone ultrasonic transmitting device array 112 set is shown; however; thepresent embodiment is not limited thereto. Four or more ultrasonictransmitting devices may be used to further enhance the directivity ofan ultrasonic beam, or two ultrasonic transmitting devices 111 may beused.

On the other hand, the ultrasonic receiver 13 is arranged on the sameplane on which the ultrasonic transmitter 11 is provided. In an exampleof FIG. 2, two ultrasonic receiving devices 131 are provided on the bothends of a side surface of the measuring apparatus 1. The ultrasonicreceiving devices 131 may also be composed of, for example, ultrasonicsensors, as with the ultrasonic transmitter 111.

A reception-phased array is composed of two ultrasonic receiving devices131. When two ultrasonic receiving devices 131 are used, a receptiontime interval difference can be provided relative to reflected waves byplacing the ultrasonic receiving devices 131 apart in a horizontaldirection. The number of the ultrasonic receiving devices 131 is notlimited to two. One ultrasonic receiving device 131, or three or moreultrasonic receiving devices 131 may be placed.

The arrangement of the ultrasonic transmitter 11 and the ultrasonicreceiver 13 is not limited to the example shown in FIG. 2, and may beany arrangement, as long as they are placed at positions where thesurrounding environment can be measured. An ultrasonic sensor capable ofcombination use of transmission and reception may be used withoutseparating ultrasonic waves for transmission and for reception as shownin FIG. 2.

Next, a scanning example of a transmission signal in the ultrasonictransmitter 11 according to the first embodiment will be explained inreference to FIG. 3.

The ultrasonic transmitter 11 transmits a transmission signal which isto be in the form of an impulse waveform once or plural times. Aftertransmitting the transmission signal once, the processing is transferredto a reception time period. The ultrasonic receiver 13 stopstransmission of the ultrasonic wave and continues receiving a reflectedwave during the reception time period, on the basis of a round-trip timeperiod of the maximum attainment distance in the measurementenvironment.

As shown in FIG. 3, the measuring apparatus 1 according to the presentembodiment performs a scanning operation with a transmitting beam 302 innine directions within a scanning range of ±45 degrees with respect to afront direction of the ultrasonic transmitter 11. That is, the scanningdirection of the transmitting beam is successively changed by 10degrees. The transmission signal is reflected by an object 303, and areceived signal as a reflected wave can be obtained. The received signalis received by two ultrasonic receiving devices 131, and thus tworeceived signals can be obtained in the transmission in one direction.As a result, one received data includes 18 received signals (ninedirections×two received signals=18). A measuring range 301 is notlimited to the scanning range of ±45 degrees, and may be set at a user'sdiscretion.

In adjacent transmitting beams 302, the scanning operation is performedso that portions in the range of the beam overlap one another. That is,an overlapping range 304 is formed between each transmitting beam 302.With this configuration, scanning can be carried out without omission inthe measuring range 301.

Next, the operation during learning of the measuring apparatus 1according to the first embodiment will be explained in reference to theflowchart shown in FIG. 4.

The measuring apparatus 1 measures a distance between the measuringapparatus itself and an object around the measuring apparatus in a givenmeasuring range.

In step S401, the multi-dimensional range sensor 21 measures asurrounding environment and acquires 2-dimensional range information atleast within the measuring range.

In step S402, the answer data storage 22 acquires the 2-dimensionalrange information as answer data.

In step S403, the ultrasonic transmitter 11 transmits a transmissionsignal in one transmitting direction within a given measuring range,based on control information. The measuring range may be included in thecontrol information.

In step S404, the ultrasonic receiver 13 receives, as a received signal,reflected waves of the transmission signal transmitted in step S403.

In step S405, the transmitting controller 12 determines whether or notthe transmission signal has been transmitted in all directions withinthe measuring range. If the transmission in all of the directions hasbeen completed, the processing proceeds to step S406, and if thetransmission in all of the directions has not yet been completed, theprocessing returns to step S403 to repeat the same processing.

In step S406, the received data storage 23 correlates a transmittingdirection with a received signal in the transmitting direction andstores them as a set of received data.

In step S407, the analyzer 24 determines whether or not a data volumenecessary for machine learning has been acquired. With respect to thedetermination of a data volume necessary for machine learning, theanalyzer 24 may determine that a necessary data volume has beenobtained, for example, if the number of acquired learning data 603 isequal to or more than a threshold.

If data necessary for machine learning has been acquired, the processingproceeds to step S409. If the data necessary for machine learning hasnot yet been acquired, the processing proceeds to step S408 to furtheracquire data.

In step S408, an environment to be measured is changed. This is becausereceived data in various environments is obtained to perform machinelearning. As a method to change an environment of a measurement subject,the measuring apparatus 1 may be manually moved, or the measuringapparatus 1 may be mounted on a mobile robot so that an environment ofthe measurement subject is automatically changed by causing the mobilerobot to move appropriately every time one measurement is finished. Incontrast, the measuring apparatus 1 may be fixed so that the environmentof the measurement subject is changed by moving an object existingaround the measuring apparatus 1. Afterward, the processing returns tostep S401 to repeat the same processing.

In step S409, the analyzer 24 performs machine learning using thereceived data and the answer data, and calculates an estimation formulaas a learning result. With the above processing, the operation of themeasuring apparatus 1 during learning is finished.

It is sufficient that a correlation between answer data and receiveddata when the measuring apparatus 1 has measured at a certain positionis ensured, and the order of steps is not limited to the order in whichmeasuring processing by an ultrasonic wave is performed after themeasuring processing by 2-dimensional range sensors. That is, themeasurement by 2-dimensional sensors may be performed after themeasurement processing by an ultrasonic wave, or the measurement by2-dimensional range sensors and the measurement by ultrasonic sensorsmay be performed at the same time.

FIG. 5 is time-series data (may be referred to as waveform data) ofsignal strength of a received signal corresponding to a transmissionsignal transmitted in a certain direction. The vertical axis shows thesignal strength, and the horizontal axis shows an elapsed time. From thetop of the waveform data, 501 denotes waveform data of a received signalobtained by a first ultrasonic receiver; 502 denotes waveform data of areceived signal obtained by a second ultrasonic receiver; 503 denoteswaveform data of a transmission signal from an ultrasonic transmittingdevice array of the right row; and 504 denotes waveform data of atransmission signal from an ultrasonic transmitting device array of thecenter row.

If explained in the time-series, first, as shown in the waveform data503 and the waveform data 504, an ultrasonic pulse is transmitted as atransmission signal.

A first peak 511 (local maximum value) of the waveform data 501 and thewaveform data 502 is a peak attributable to a transmission signaldirectly received by the ultrasonic receiving devices 131 without beingreflected anywhere. A second peak 512 is a peak attributable to areflected wave from the floor. A third peak is a maximum peak, which isattributable to a reflected waveform from the nearest object in thesurrounding environment. A fourth peak 514 and a fifth peak 515 arepeaks assumed to be attributable to reflected waves from the second andthe third nearest objects in the surrounding environment.

In the present embodiment, waveform data can be obtained which includesinformation that cannot be obtained only with a first reflected wave byusing not only a value of the peak 513 which is a reflected wave fromthe nearest object but also using even the values of the peak 514 andpeak 515 as received signals. The waveform data may be a waveform of asignal value of the received signal that is received by the ultrasonicreceiving device 131, or may be an envelope waveform obtained bydetecting an envelope of a signal value of the received signal, or maybe an aggregate of respective peak values.

Next, a conceptual diagram of machine learning at the analyzer will beexplained in reference to FIGS. 6 and 7.

FIG. 6 is a conceptual diagram of learning data according to the presentembodiment.

The analyzer 24 performs machine learning by using, as learning data603, a pair of a received data group (a group of waveforms) 601 of eachdirection (nine directions in the present embodiment) and corresponding2-dimensional range information 602 as answer data. Note that in thepresent embodiment, the 2-dimensional range information 602 is displayedas a map where a distance from a starting point to an object on a2-dimensional plane is plotted at each azimuth angle around the startingpoint, however; the 2-dimensional range information is not limitedthereto, and may be a set of data where directional information (orcoordinate information) is correlated with range information. Thestarting point corresponds to a position of the multi-dimensional rangesensor 21.

The measuring apparatus 1 acquires a plurality of such learning data 603while changing a surrounding environment to be measured to acquire adata volume necessary for machine learning. Afterward, the analyzer 24performs machine learning to calculate an estimation formula as alearning result.

FIG. 7 is a schematic diagram of deep learning for use in machinelearning.

Deep learning is a technique of machine learning using a multi-layerneural network and includes an input layer 701, a plurality ofintermediate layers 702, and an output layer 703, and is characterizedin that the plurality of intermediate layers 702 are present.

It is common that in the multi-neural network, data is associated withone another only between one layer and another layer. The multi-layerneural network assumed in the present embodiment is a feedforward typewhere data proceeds toward the input layer 701, the intermediate layers702, and the output layer 703 in this order, and data is not fed back tothe input layer 701.

The analyzer 24 causes the multi-layer neural network to perform machinelearning based on learning data which is a pair of a group of receiveddata of each direction and corresponding 2-dimensional range informationas answer data and calculates an estimation formula for estimatinganswer data from the group of received data.

Next, the measuring apparatus 1 according to the first embodiment duringmeasuring will be explained in reference to the block diagram shown inFIG. 8.

The measuring apparatus 1 according the first embodiment duringmeasuring includes an ultrasonic transmitter 11, a transmittingcontroller 12, an ultrasonic receiver 13, and an estimator 14.

The estimator 14 estimates range information from a received signalpresently measured based on preliminarily obtained received signals andinformation on a distance to an object. Specifically, the estimator 14receives control information from the transmitter controller 12, whichhas been obtained from the analyzer 24, and receives a received signalfrom the ultrasonic receiver 13. The estimator 14 estimates rangeinformation corresponding to a transmitting direction based on controlinformation related to a transmission signal transmitted across themeasuring range, received data, and an estimation formula. The rangeinformation is information related to the transmitting direction of thetransmission signal, and a distance between the nearest object and themeasuring apparatus 1. 2-dimensional range information obtained by a2-dimensional range sensor may be used as range information.

Next, the operation of the measuring apparatus during measuring will beexplained in reference to the flowchart shown in FIG. 9.

The measuring apparatus 1 performs processing from step S403 to stepS405 for a surrounding environment to be measured.

In step S901, the estimator 14 estimates 2-dimensional range informationfrom transmitting directions of all directions in the measuring rangeand received signals, based on an estimation formula.

After the 2-dimensional range information is estimated, the estimated2-dimensional range information is transmitted externally. As an exampleof use of estimated 2-dimensional range information, for example, a mapgenerator (not illustrated) that has received 2-dimensional rangeinformation may generate a distance map where 2-dimensional rangeinformation is depicted on a plane view, and a display (not illustrated)may display the distance map. The distance map may be used inidentification of self-position of the measuring apparatus.

According to the first embodiment described above, the measuringapparatus 1 performs machine learning using received signals including aplurality of reflected waves, as a reflected wave of a transmissionsignal to determine an estimation formula. That is, values of reflectedwaves from objects other than the nearest object are included asinformation in waveform data, even if the values thereof cannot beextracted independently of the waveform data. Therefore, a highlyaccurate estimation formula can be determined by having the measuringapparatus perform machine learning without reducing the informationvolume of waveform data formed from such a surrounding environment.

Furthermore, by using a calculated estimation formula, 2-dimensionalrange information can be accurately calculated from received dataobtained by measuring a surrounding environment. Accordingly, ameasuring apparatus that acquires 2-dimensional or 3-dimensional rangeinformation can be realized by low-cost implementation. That is, ahighly accurate measuring apparatus can be realized by low-costimplementation using ultrasonic waves.

Second Embodiment

In a second embodiment, a case is assumed where a surroundingenvironment is measured in a state where an object around the measuringapparatus 1 or the measuring apparatus 1 itself is moving. For example,if the measuring apparatus 1 comes near to the object in thesurroundings, the frequency (may be referred to as a transmissionfrequency) of a transmission signal becomes higher than the frequency ofa reflected wave due to the Doppler Effect. In contrast, if themeasuring apparatus 1 gets away from the object in the surroundings, thetransmission frequency of the transmission signal becomes lower than thefrequency of a reflected wave.

Therefore, the second embodiment differs from the first embodiment inthat a received signal is separated into signals having a plurality offrequency bands to perform machine learning with the respective signals,and an estimation formula is calculated for each of the signals havingthe plurality of frequency bands.

The measuring apparatus 1 according to the second embodiment duringlearning will be explained in reference to the block diagram shown inFIG. 10. The measuring apparatus 1 during measuring will be explained inreference to the block diagram shown in FIG. 11.

The operations of the measuring apparatus 1 according to the secondembodiment are the same as in the first embodiment, except foroperations other than those of the ultrasonic receiver 13 and thereceived data storage 23.

The ultrasonic receiver 13 includes a plurality of ultrasonic receivingdevices 131 and a plurality of bandpass filters 132.

The plurality of bandpass filters 132 respectively pass only a signalwith a specific frequency band for received signals from the ultrasonicreceiving devices 131, and generate filtered received-signals.

In the second embodiment, a first filter that passes a signal with thesame frequency as the frequency band of a transmission signal, a secondfilter that passes a signal with a frequency band higher than thefrequency band of the transmission signal, and a third filter thatpasses a signal with a frequency band lower than the frequency band ofthe transmission signal are used. That is, from one received signal,three filtered received-signals which are different in frequency bandare generated.

The range of frequency bands higher than the frequency band of thetransmission signal, and the range of frequency bands lower than thefrequency band of the transmission signal are not limited thereto. Forexample, if the measuring apparatus 1 itself moves, frequency bands tobe extracted may be determined based on the moving speed of themeasuring apparatus, and if an object present in the surroundingenvironment moves, frequency bands to be extracted may be determinedbased on the moving speed, etc. of the object.

The received data storage 23 receives the filtered received-signals thathave passed through each of the bandpass filters of the ultrasonicreceiver 13 and stores them as a set of received data.

Next, the operation of the measuring apparatus 1 according to the secondembodiment during learning will be explained in reference to theflowchart shown in FIG. 12.

In step S1201, the multi-dimensional range sensor 21 measures asurrounding environment to obtain 2-dimensional range information beforemeasurements by means of ultrasonic waves.

In step S1202, the ultrasonic wave transmitter 11 transmits atransmission signal in one direction within a measuring range, based oncontrol information.

In step S1203, the ultrasonic receiver 13 receives, as a receivedsignal, a reflected wave of the transmission signal transmitted in stepS1202.

In step S1204, the plurality of bandpass filters 132 of the ultrasonicreceiver 13 generate filtered received-signals with a plurality offrequency bands.

In step S1205, the transmitting controller 12 determines whether or notthe transmission signal has been transmitted in all directions withinthe measuring range. If the transmission in all directions has beencompleted, the processing proceeds to step S1206, and if thetransmission in all directions has not yet been completed, theprocessing returns to step S1201 to repeat the same processing.

In step S1206, after the measurement using ultrasonic waves, themulti-dimensional range sensor 21 measures the surrounding environmentagain to acquire 2-dimensional range information.

In step S1207, the answer data storage 22 stores the 2-dimensional rangeinformation. That is, two types of answer data obtained before and afterthe measurement using ultrasonic waves are stored in the answer datastorage 22.

In step S1208, the received data storage 23 correlates a transmittingdirection with a filtered received-signal in the transmitting directionand stores the correlation as received data. Specifically, twoultrasonic receiving devices×nine directions×three filteredreceived-signals=54 filtered received-signals are stored as a set ofreceived data in the received data storage 23.

In step S1209, the analyzer 24 determines whether or not a data volumenecessary for machine learning has been obtained. If data necessary formachine learning has been acquired, the processing proceeds to stepS1210, and if data necessary for machine learning has not yet beenacquired, the processing returns to step S1201 and repeats the sameprocessing to further acquire data.

In step S1210, the analyzer 24 performs an analysis based on the machinelearning using the received data and answer data to calculate anestimation formula before the measurement using ultrasonic waves and anestimation formula after the measurement using ultrasonic waves. Withthe operations described above, the operations of the measuringapparatus 1 according to the second embodiment are finished.

Next, the operation of the measuring apparatus 1 during measuringaccording to the second embodiment will be explained in reference to theflowchart shown in FIG. 13.

Step S403, Step S404, and Step S405 are the same as in the firstembodiment.

In Step S1301, the estimator 14 estimates 2-dimensional rangeinformation before and after the measurement using ultrasonic waves,based on the received data and the two estimation formulae.

According to the second embodiment presented above, the measuringapparatus performs machine learning based on received signals in aplurality of frequency bands and estimates estimation formulae. Withthis configuration, measuring apparatus that acquires 2-dimensional or3-dimensional range information can be realized by low-costimplementation as with the first embodiment, even when the measuringapparatus itself moves, and even when moving objects are present.

Third Embodiment

The third embodiment differs from the above-mentioned embodiments inthat data measured by a 1-dimensional range sensor (e.g., a laser rangesensor) capable of measuring a distance in one direction is included inreceived data.

The measuring apparatus 1 according to the third embodiment duringlearning, and the measuring apparatus 1 during measuring will beexplained respectively in reference to the block diagram shown in FIG.14 and the block diagram shown in FIG. 15.

The measuring apparatus 1 according to the third embodiment includes a1-dimensional range sensor 15 in addition to the measuring apparatusaccording to the first embodiment during measuring.

The 1-dimensional range sensor 15 includes a transmitter(not-illustrated) that transmits a laser, and a receiver(not-illustrated) that receives a laser reflected from an object. The1-dimensional range sensor 15 can measure 1-dimensional rangeinformation based on a phase difference between the transmitted laserand the reflected laser or a round trip time therebetween, and generatesthe 1-dimensional range information.

The received data storage 23 receives the 1-dimensional rangeinformation from the 1-dimensional range sensor 15. The received datastorage 23 combines a received signal measured once in a measuring rangewith the 1-dimensional range information to store the combination as aset of received data.

An arrangement example of the 1-dimensional range sensor 15 according tothe third embodiment will be explained in reference to FIG. 16.

As shown in FIG. 16, the 1-dimensional range sensor 15 is arranged onthe same plane on which the ultrasonic transmitter 11 and the ultrasonicreceiver 13 are provided. The 1-dimensional range sensor 15 measures,for example, a distance in one frontward direction to obtain1-dimensional range information.

Next, a scanning example of the ultrasonic transmitter 11 according tothe third embodiment will be explained in reference to FIG. 17.

The 1-dimensional range sensor 15 measures a distance in a frontdirection by a laser 1701 and acquires highly accurate 1-dimensionalrange information. On the other hand, a measurement by ultrasonic wavesaccording to the present embodiment is the same as in theabove-mentioned embodiments. Not only 1-dimensional information in thefront direction but also 1-dimensional range information in any onedirection within the measuring range may be acquired by changing theposition of the 1-dimensional range sensor 15 to be set.

According to the third embodiment presented above, a distance of asurrounding object in a certain one direction, such as a frontdirection, is measured accurately by the properties of a laser, andreceived data obtained using ultrasonic waves and the accurate data arecombined together, and the combined data is stored as an input ofmachine learning. With this configuration, it is considered that thematching accuracy between the input of the machine learning and2-dimensional range information as answer data is improved, as result,making it possible to improve the accuracy of machine learning and toimprove the estimation accuracy of 2-dimensional range information.

In the above-mentioned embodiments, a case of estimating 2-dimensionalrange information related to a 2-dimensional plane is explained;however, 3-dimensional range information may be estimated bytransmitting a transmission signal in an azimuth direction and in adirection of an elevation angle so that reflective waves thereof arereceived as received signals. In this case, as for the range informationto be acquired as answer data, it is advisable to acquire 3-dimensionalrange information by expanding a measuring range by a 2-dimensionalrange sensor to a 3-dimensional space.

As explained above, a case is assumed where a learning result isgenerated by performing machine learning based on data preliminarilyobtained in an environment in which the measuring apparatus willmeasure; however, the configuration is not limited thereto.

For example, a learning result generated based on data measured by aplurality of measuring apparatuses in various environments is stored byuploading in an external server (not illustrated) such as a cloudserver. If a certain measuring apparatus performs a measurement, forexample, the estimator 14 may acquire (or download), from an externalserver, a learning result obtained in an environment similar to anenvironment in which a user wants to measure and read the learningresult, and then the measurement may be carried out by the measuringapparatus 1. This configuration makes it possible to skip preliminarylearning and to carry out an immediate measurement of a surroundingenvironment.

The instructions shown in the processing sequence in the above-describedembodiment may be executed based on a software program. The same effectas that of the above-described detection apparatus may be obtained bystoring the program in a general-purpose computer system in advance, andthen reading the program. The instruction described in theabove-mentioned embodiment may be recorded as a computer-executableprogram in a magnetic disk (flexible disk, hard disk, etc.), an opticaldisk (CD-ROM, CD-R, CD-RW, DVD-ROM, DVD+R, DVD+RW, Blu-ray (registeredtrademark) Disc, etc.), a semiconductor memory, or a similar type ofrecoding medium. Any recording format may be employed as long as theformat is readable in a computer or an embedded system. The sameoperation as that of the detection apparatus of the above-describedembodiment may be realized when the computer reads the program from therecording medium and the instructions described in the program isexecuted by the CPU or processing circuitry based on the program. It isa matter of course that the computer may acquire and read the programthrough a network. In addition, an OS (operation system) running on thecomputer, a database management software, an MW (middleware) such as anetwork may perform some of the respect processes based on theinstruction of the program stored in the computer or the embedded systemfrom the recording medium for realizing this embodiment. Furthermore,the recording medium in this embodiment is not limited to a mediumindependent from the computer or the embedded system, and may be arecording medium which downloads the program transferred through a LANor the Internet, and stores or temporarily stores the program. Inaddition, the number of recording mediums is not limited to “1”. Even acase where the process in this embodiment is performed from a pluralityof recording mediums is also included in the case of the recordingmedium in this embodiment, and any configuration of the medium may beemployed.

Further, the computer or the embedded system in this embodiment performsthe respective processes in this embodiment based on the program storedin the recording medium, and may be configured by any one of a devicesuch as a personal computer or a microcomputer and a system where aplurality of devices are connected through a network. In addition, thecomputer in this embodiment is not limited to the personal computer, andincludes an arithmetic processing device included in an informationprocessing apparatus, and a microcomputer. The computer in thisembodiment collectively refers to an apparatus or a device which canrealize the functions in this embodiment by a program.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the inventions. Indeed, the novel embodiments described hereinmay be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the embodimentsdescribed herein may be made without departing from the spirit of theinventions. The accompanying claims and their equivalents are intendedto cover such forms or modifications as would fall within the scope andspirit of the inventions.

What is claimed is:
 1. A measuring apparatus comprising: an ultrasonictransmitter that transmits, as a transmission signal, an ultrasonic beamin a plurality of directions; an ultrasonic receiver that receives, asreceived signals, reflected waves of the transmission signal from theplurality of directions, one received signal including a plurality ofreflected waves when the transmission signal is transmitted to onedirection of the plurality of directions; and an estimator thatestimates range information from the received signals, based onpreliminarily obtained received signals and a preliminarily obtaineddistance to an object.
 2. The apparatus according to claim 1, whereinthe received signals each represents a waveform including a plurality oflocal maximum values.
 3. The apparatus according to claim 1, wherein theultrasonic transmitter transmits the transmission signal whileperforming a scanning operation in the plurality of directions so thatadjacent portions of the ultrasonic beam overlap.
 4. The apparatusaccording to claim 1, further comprising: an analyzer that performsmachine learning using the received signals and multi-dimensional rangeinformation related to a distance from the apparatus to an object, andgenerates a learning result including an estimation formula, themulti-dimensional range information being obtained by amulti-dimensional range sensor.
 5. The apparatus according to claim 1,further comprising: a plurality of bandpass filters that generate aplurality of filtered received-signals from the received signals bypassing a signal having a specific frequency band, wherein the estimatorestimates the range information from the plurality of filteredreceived-signals, based on a plurality of preliminarily obtainedfiltered received-signals and a distance to the object before and aftermeasuring using an ultrasonic beam.
 6. The apparatus according to claim1, further comprising: a one-dimensional range sensor that measures adistance from the apparatus to an object in a given direction to obtainone-dimensional range information, wherein the estimator estimates therange information from the one-dimensional information and the receivedsignals, based on preliminarily obtained reflected waves from theplurality of directions, preliminarily obtained one-dimensional rangeinformation and a preliminarily obtained distance to the object.
 7. Theapparatus according to claim 3, wherein each of the plurality ofdirections is an azimuth direction in a two-dimensional plane.
 8. Theapparatus according to claim 3, wherein the plurality of directions isan azimuth direction and a direction of an elevation angle in athree-dimensional space.
 9. The apparatus according to claim 1, whereinthe estimator estimates the range information, based on a learningresult related to the preliminarily obtained received signals and thepreliminarily obtained distance to the object.
 10. A measuring methodcomprising: transmitting, as a transmission signal, an ultrasonic beamin a plurality of directions; receiving, as received signals, reflectedwaves of the transmission signal from the plurality of directions, onereceived signal including a plurality of reflected waves when thetransmission signal is transmitted to one direction of the plurality ofdirections; and performing machine learning using the received signalsand multi-dimensional range information related to a distance from ameasuring apparatus to an object to generate a learning result includingan estimation formula, the multi-dimensional range information beingobtained by a multi-dimensional range sensor.
 11. A measuring methodcomprising: transmitting, as a transmission signal, an ultrasonic beamin a plurality of directions; receiving, as received signals, reflectedwaves of the transmission signal from the plurality of directions, onereceived signal including a plurality of reflected waves when thetransmission signal is transmitted to one direction of the plurality ofdirections; and estimating range information from the received signals,based on preliminarily obtained received signals and a preliminarilyobtained distance to an object.